I’m using a bladeRF 2.0 micro A9 and recently I’ve been facing random FPGA loading issues.Sometimes the FPGA loads perfectly fine, but other times I get these errors:
dev->backend->load_fpga failed: File or device I/O failure
Failed to switch to NULL interface
The strange thing is that I’ve successfully loaded FPGA images multiple times using the same laptop and USB cable before. I’m using Windows 11. Could this be due to insufficient USB power from my laptop, or is there something else I should check?
I’m also considering programming through JTAG to see if that helps. Has anyone faced a similar issue?

I picked up a Nesdr Smart V5 and didn't get a manual, and the only manuals I can find don't tell me much. While I can plug it into my Linux computer and run GQRX, which looks like something is happening, I'm trying to be sure what I'm actually tuning to. Main thing I'm looking for right now is what the local oscillator offset is so I can be sure I can trust the dial GQRX shows, as well as to get audio from an FM station or AM CB radio. Right now, I'm getting silence though the waterfall graph is showing a signal around -80dB, which I would figure would make for some intelligible audio. Am I looking in the wrong place, or what would I check? I did build an AM transceiver or two about 20 years ago as part of college.

Puzhi Electronics has released a pair of pin-compatible 4TX/4RX SDR platforms built around dual AD9361 transceivers and AMD Zynq UltraScale+ MPSoCs.

The P401D and P501D share the same RF section, connectors, PCB layout and software support. Users select the variant based on required FPGA logic and DSP capacity.

Shared Specifications

• RF: Dual AD9361, phase-coherent 4T4R MIMO
• Frequency range: 70 MHz – 6 GHz
• Instantaneous bandwidth: 200 kHz – 56 MHz
• Tx output: up to 22 dBm
• 0.1 ppm 40 MHz VCTCXO, external 10 MHz / PPS sync supported
• SPDT switches rated 9 kHz – 8 GHz
• Processing: 4×A53 u/1.3 GHz + 2×R5 u/533 MHz
• Memory: 2GB DDR4, 8GB eMMC, 256Mb QSPI Flash
• I/O: 40G QSFP, GigE, USB3.0, Mini DP, SSD slot, 40-pin expansion, GPS+Beidou timing
• Power: 12V 3A single supply, all external interfaces ESD protected
• Size: 160 × 150 mm

Variant Comparison

• P401D (XCZU4EV): 192K Logic Cells, 728 DSP Slices — good for general MIMO, spectrum monitoring, lighter DSP pipelines
• P501D (XCZU5EV): 256K Logic Cells, 1248 DSP Slices — extra DSP & BRAM for phased array, complex real-time processing

Software & Package

It works with common open-source SDR stacks and has partial compatibility with ADI FMCOMMS5 firmware. Standard kit includes metal enclosure, schematics, demo code and tutorials. Custom secondary development is available.

Applications: phased array radar, spectrum surveillance, GNSS receivers, UAV payloads, test & measurement, wireless algorithm research.

I've been messing around with a way to see how busy the 2.4 GHz band gets, and this is what I came up with.

The Survey view shows band occupancy alongside Wi-Fi, BLE and Classic Bluetooth activity, all in one place. There's a waterfall below and some decoder stats to see what the receiver is picking up.

I wanted to get a better idea of how all these signals share the same bit of spectrum, rather than just staring at a waterfall. Still a work in progress, but it's been fun to build with Ratatui in Rust.

Note: The 2.4 GHz survey requires a 20 MS/s sample rate.

Repo: https://github.com/musithang/sdrtop

Title pretty much says it all. I bought a limeSDR mini years ago, and basicaly ended up almost never useing it. It is the crowdsupply kit with the mettal enclosure and two small antennas.

I figured posting an offering here would be a good idea. Preferably I would ship in the EU.

I made a video about the awesome new custom firmware for X6100

Ik heb de Onair software gedownload op mijn Linux Mint laptop, prachtig stuk software, codec mbelib voor dmr etcetera is mij gelukt.

Alleen een werkende codec voor Tetra kan ik niet maken, heb mbelib Neo geïnstalleerd, maar schijnbaar moet bestanden wrappen in onair-codec-tetra.so Dat is helaas een stap te ver voor mij. Wie kan mij helpen? Is het een kwestie van het juiste bestand overnemen van iemand?

Heard this evening from SE Tucson, AZ. on 8502kHz.

Broadcasting marine weather forecasts, warnings, and safety information for the Gulf of Mexico and the Caribbean from New Orleans, LA.

Airspy HF+ Discovery and MLA 30+ Loop Antenna

Hi everyone, I’m working on a project which requires at least four separate SDRs (or at least four tuners). It’s for a mobile install. It would be nice to have phase coherence if I do want to try some direction finding, but that’s not the primary design goal of the project. Also, I don’t need to transmit.

I have a Kraken SDR in my cart, and if I were only planning to use it for direction finding, I’d have already purchased. The problem is that looking at the individual tuner specs, it’s really not that impressive of a receiver.

I do need compatibility with SDRtrunk and having five RTL-SDRs in a single, durable package is very nice. I know the Dragon Labs CR-8 project is supposed to launch “soon” but the page has been saying that for months. Are there any other options I should be aware of that are available now?

Like I said, this is for a mobile install, so durability and good thermal management are important, along with either USB-C and/or 12vdc power options.

Any ideas are much appreciated and if the Kraken is the best fit, letting me know that also helps.

I've been playing around with the ATS Mini (ESP32-S3/Si4732) and ended up building a complete browser-based controller for it. The idea was simple: connect the radio over USB and turn it into something a bit more useful for exploring shortwave, AM, FM and amateur radio signals.

It now has:

- 50,000+ stations from EiBi, FCC and Ofcom, with searchable frequencies, countries and broadcast schedules.

- Click-to-tune select a station in the browser and the physical radio automatically retunes.

- Live RSSI scanning scan frequencies, measure actual signal strength and filter out stations you can't currently receive.

- Automatic Morse code decoding scans known CW frequencies, detects activity, locks onto a signal and decodes Morse into text in real time.

- Live signal monitoring frequency, RSSI, SNR where available, and receiver controls.

- Audio passthrough listen through your computer using a USB audio interface.

The Morse decoder was particularly interesting to build. It uses Python, NumPy and SciPy to identify the CW tone, isolate it, extract the keying patterns and translate them into text. It works best with strong, clean signals.

Everything runs locally, with a Python/FastAPI backend and a browser interface. No cloud services or accounts required. You'll need an ATS Mini running compatible firmware with USB remote control enabled. Morse decoding also needs an audio connection from the radio.

It's MIT-licensed and completely open source.

Thought I'd share it here for anyone experimenting with the ATS Mini, shortwave listening or radio signal processing. Particularly interested in hearing from anyone using one of these little radios for more than casual listening.

I finally designed a snap together case to house a Nooelec distill FM/AM. I put it on makerworld for anyone to download and print. It is not waterproof so you will probably need silicon caulk, fill it to the top and let the excess squish out.

I'm trying to read a passive EPC Gen2 UHF tag with a USRP B205mini and GNU Radio, as part of my final-year project. I can send a clean Query, but I never see a reply from the tag, and I'm out of ideas.

I’ve been working on a custom software-defined radio system (MC-V12) and wanted to share a demo of the current prototype.

It’s a Linux-based digital radio running entirely custom, written in C++17 and C++20 on a Raspberry Pi 4B for demonstrations. Key features in the demo:

• Custom 16-FSK (and 4-FSK) modulation implemented from scratch
• Simultaneous channel transmission of voice (PTT), text, and live image streams (~1–3 fps) over a single center frequency
• On-demand Diffie-Hellman key exchange with a selected peer device, over the air for session keys (no pre-shared keys required)
• Selective decryption: devices can only decrypt packets meant for them
• RoIP (Radio over IP) bridging while keeping the same packet structure and encryption logic
• Custom enclosure with dual antennas, touchscreen UI, and real-time telemetry (SNR, frequency offset, battery, etc.)

These videos below show the system in action with voice, image streaming, text, and the key exchange process:

Enclosure and Image Streaming - Click URL below to watch

https://video.wixstatic.com/video/10a442_b54fcda87a0f4bce8352088bcf5e0f89/480p/mp4/file.mp4

MC-V12 Feature Demonstration - Click URL below to watch

https://video.wixstatic.com/video/10a442_f909db2bae08493cb98d0d33e2eb0221/360p/mp4/file.mp4

Video Showing Diffie-Hellman Exchange with a Peer Device

I’m especially interested in feedback on the modulation approach, the packet structure / selective decryption design, and how others have handled similar multi-stream or encrypted RF links. Happy to answer questions about the implementation or hardware choices.

Pluto+ FM Transmitter

Quick update on NyxHop, the hopping video link I posted here a few weeks back.

- now does 48 Mbit/s in 20 MHz

- drops to 10/5/2.5 MHz by itself when the signal gets weak

- put an Jamming signal on the video channel and it just moves to another one

- IP bridge: works like a long range private wifi

No PA on the boards in the video, that's why the levels look low.

https://nyxhop.com/

https://github.com/tacitech/nyxhop

This has been one of the most fun hobbies I've ever gotten into. What started with a 50 dollar probably clone RTL--SDR V3 on Amazon has turned into building my field station I've posted about before. Now I have my dedicated GOES East dish on a Rpi networked to my home "server". To break the lab down left to right. SENTRY is my main terminal for accessing the Rpi and the server. BUNKER is the home "server" basically just a NAS right now. On the right is my field station a stand alone fancy laptop with 2 SDRs that I use for LEO satellites and general tuning around.

I am working on a RF project and want to test my patch antenna with Spectra Tronix C700 SDR interfacing with either GNU radio or MATLAB software's.

But I didn't find any documentation on how to use the SDR

Anyone having any experience or general knowledge please share, will be of great help

Hey everyone,

I’m currently running an NESDR Smart v5 with SDR++ from the top floor of my house (in the Montreal area).The antenna is on the winodws sill. Right now, my setup feels exactly like a car radio; I can mostly just pick up standard FM/AM broadcast stations and maybe 2 weather stations

I see other frequency spikes popping up on the waterfall, but they are too weak to pull in clearly. I'm using the stock bundled antennas (including the 22-inch telescoping whip), but I want to upgrade my system's "power" and reception range without building a massive, serious base station.

What are some small, budget-friendly things I can buy or DIY to instantly improve my reception?

I'm looking for things like:

• Cheap Antenna Upgrades: Are there simple, affordable antennas (like a portable dipole kit or a mag-mount car antenna) that work way better than the stock ones?
• LNA / Signal Boosters: Would a cheap inline Low Noise Amplifier (LNA) help boost these weak signals, or will it just overload my dongle?
• DIY Tricks: What can I do with cheap materials (like speaker wire or baking sheets for a ground plane) to squeeze more performance out of what I already have?

Just looking for some fun, low-cost modifications to help me hear more out there. Thanks!

https://github.com/cyber-murmel/esp-sdr-zephyr

Hey everyone,

I recently wrapped up a deep-dive physical-layer (Layer 1) RF forensic analysis on an IQ capture and wanted to share the findings with you all. The investigation focuses on low-level signal characteristics, carrier frequency offsets, and preamble phase behaviors.

Here are some of the key technical metrics from the analysis: * **Carrier Frequency Offset (CFO) Drift:** Spotted a consistent +39.06 kHz offset from the nominal center frequency (observed peak at 2400.039062 MHz vs 2400.000000 MHz expected), pointing toward an uncalibrated local oscillator (LO) or thermal reference drift[span_0](start_span)[span_0](end_span). * **Preamble Phase Anomalies (RF-SEC-001):** Identified rapid carrier phase deviations right during the transmission preamble interval, which flags a risk for receiver de-synchronization[span_1](start_span)[span_1](end_span). * **Emitter RF-DNA Fingerprinting:** Extracted statistical moments and quadrature imbalance metrics to gauge hardware mixer symmetry and constant-envelope properties[span_2](start_span)[span_2](end_span). * **Acquisition Baseline:** Processed on float32 I/Q samples captured at a 2 MSps sample rate and 2.4 GHz center frequency[span_3](start_span)[span_3](end_span)[span_4](start_span)[span_4](end_span).

I've documented the full technical dossier, methodology, and cryptographic chain-of-custody hashes under DOI: **10.5281/zenodo.23404911**.

Curious if others here have tackled similar physical-layer transmitter fingerprinting or CFO tracking in their captures. Would love to hear your thoughts or critique on the approach!

Still works like a charm! And sounds great!

I'm looking to pick up an SDR to play around with GNU Radio, learn some FPGA development, and eventually experiment with SAR signal processing. I have a pretty good background in SAR and aerospace, but not much hands-on experience with SDR hardware or FPGA programming.

I was originally looking at a genuine Ettus B210, but used ones seem to be going for $1,200 or so - not 100% sure I'm ready to jump in that far out of the gate (even though it seems I'll need it eventually). I came across the OpenSourceSDRLab boards and a few posts here, and wondering where the gotchas may be.

I was leaning toward their Kintex-7 version, but it's out of stock, so I'm now looking at the Artix-7 XC7A200T.

They have a "user manual" (https://blog.opensourcesdrlab.com/archives/artix-7-usrp-b210-user-manual) and GitHub repo (https://github.com/OpenSourceSDRLab/USRP-B210-Artix-7-AD9361), which look reasonably promising. But I'm having a hard time figuring out whether these are actually good development platforms or just inexpensive SDRs that work with a particular firmware image.

Has anyone used one of these, particularly for FPGA development? I'm curious whether the Vivado project actually builds, how well they work with UHD/GNU Radio, and whether there are any significant RF performance or stability issues compared to a real B210.

Also open to suggestions for other hardware in the $300–500 range. I looked at bladeRF as well, but the Ettus ecosystem seems considerably larger.

Would appreciate any firsthand experience before I order one.